1. Field of the Invention
The present invention concerns a hand-held electric blower.
The invention applies to the field of air projection devices used to ‘sweep’ dry leaves or diverse trash likely to cover large surfaces such as lawns, public roadways, outside parking lots etc. The result obtained by their action is similar to that obtained by use of a conventional broom or rake. The invention concerns also the field of projection devices for treatment products such as plant protective treatment products.
These devices may be intended for professional use as well as for domestic use.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Usage of these ‘blowers’ is extremely wide-spread due to their great simplicity of use, the speed of performance of the clean-up tasks and their efficient action.
Such devices consist mainly of an air-guiding pipe featuring a proximal air inlet portion or suction pipe, a distal air outlet portion or exhaust pipe, and an axial OF centrifugal fan positioned inside the middle portion of the pipe. This fan sucks up air and delivers it in the form of an air flow enabling the pushback of the dry leaves or various trash so as to amass them in a pile that can easily be removed. This fan may be driven by a thermal engine or an electric motor.
These devices may be fitted. for propelling treatment products such as plant protective treatment products. The devices of this kind may present themselves in the form of hand-held tools or they may be attached to a user's back by means of a harness.
Patent document US-200870127448 describes a blower provided with a centrifugal fan. According to this document, the suction pipe is covered by a grid and the centrifugal fan housed in a spiral shell is directly driven by a thermal engine. However, this device is heavy, it is an energy guzzler and its operation is very noisy. Especially the fan's rotation, the passage of air over the obstacles placed in the flow (air inlet protective screen, the supports), etc., create direct noise pollution of the surroundings of the blower and for the user. Furthermore, this noise pollution generally affects the well-being of the user who is obligated to wear some kind of hearing-protection such as ear plugs, a helmet or other.
Patent documents U.S. Pat. No. 4,413,371 and DE 102007037012 present below some blowers provided with an axial fan.
In the U.S. Pat. No. 4,413,371 patent, the device is composed of a first unit comprising a thermal engine and a second unit featuring the blower system, the thermal engine being, directly coupled to the axial fan. The latter is housed at the end of a long exhaust pipe presenting decreasing width and an end extending this an outlet of thin thickness. Said blower is equipped with two operating handles. This device is complex and seems to be difficult to handle considering the weight of the thermal engine and its configuration. As a matter of fact, two operating handles are necessary for its manipulation and the end of the exhaust pipe must be kept close to the ground. Another inconvenience is the low performance of the device despite of the use of an axial fan.
In document DE-102007037012, driven by an electrical motor, the proximal air inlet portion or suction pipe is mounted in the rotational axis of the fan constituted by a number of helixes that are coupled to each other. This arrangement is supposed to improve the performance of such devices and to reduce the noise. The noise does however remain unusually high and the performance is still just as mediocre.
In summary, the various representative documents of prior art have in common such disadvantages as high energy consumption, low performance and significant noise pollution,
Objectives of the Invention
A major aim of the invention is to remedy the inconveniences of the prior art, in particular the disadvantages of the devices described in the aforementioned documents, or to lessen to a large extent the harmful effects of some of these inconveniences.
The objective of the invention is to significantly reduce the noise of the blower and, at the same time, optimize its performance.
Another objective of the invention is to propose a simple, low-cost., low-energy consuming blower that is environment-friendly and has a pleasing appearance.